this is the entire original series of BSG from late 1970's. it looks a little dated now, with the sets and costumes (and a little dialogue), but overall it's still excellent by today's standards!
you have to overlook a couple of bouts of sheer silliness, (how does a kid (Boxey) get involved in serious military matters?, how come the Viper fighters need gyroscopes in space??), but overall, the series is ACE!!
For my money, one of the best characters in it is Baltar, played (with great relish) by John Colicos, the traitor to the human race. Later on in the series, he gets written out of a few storylines, but with guest appearances from the likes of Fred Astaire (Chameleon, in The Man with Nine Lives), and Lloyd Bridges (Cmdr. Cain, The Living Legend - My favourite episode), there is enough going on so that you don't get bored.
The last episode (Hand Of God) is a good place to end the series, as it answers the question whether the mythical "Earth" really exists. This being science fiction, you're never really sure if it's meant to be 'real', or just fiction - until the last scene.